Hi Liviu,
On 28.10.2015 12:38, Liviu.Dudau@xxxxxxx wrote:
On Tue, Oct 27, 2015 at 05:38:41PM +0100, Tomasz Nowicki wrote:
Architectures which support PCI_DOMAINS_GENERIC (like ARM64)
cannot call pci_bus_assign_domain_nr along ACPI PCI host bridge
initialization since this function needs valid parent device reference
to be able to retrieve domain number (aka segment).
We can omit that blocker and pass down host bridge device via
pci_create_root_bus parameter and then be able to evaluate _SEG method
being in pci_bus_assign_domain_nr.
Note that _SEG method is optional, therefore _SEG absence means
that all PCI buses belong to domain 0.
Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
---
drivers/acpi/pci_root.c | 2 +-
drivers/pci/pci.c | 32 +++++++++++++++++++++++++++-----
2 files changed, 28 insertions(+), 6 deletions(-)
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 850d7bf..e682dc6 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -839,7 +839,7 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
pci_acpi_root_add_resources(info);
pci_add_resource(&info->resources, &root->secondary);
- bus = pci_create_root_bus(NULL, busnum, ops->pci_ops,
+ bus = pci_create_root_bus(&device->dev, busnum, ops->pci_ops,
sysdata, &info->resources);
Not sure this change should be in this patch, I don't see the relation.
To put it differently: I think the patch should introduce the retrieval of the
domain number from _SEG method and leave the passing of a valid host bridge device
to a more appropriate patch.
I wanted to highlight that ACPI kernel using PCI_DOMAINS_GENERIC needs
to have both in place:
1. Obtaining domain from _SEG method
2. And host bridge device reference for which we can call _SEG.
But you are right, it will be more clear if I split up patch and
describe it in separate changelog.
if (!bus)
goto out_release_info;
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 6a9a111..17d1857 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -25,6 +25,7 @@
#include <linux/device.h>
#include <linux/pm_runtime.h>
#include <linux/pci_hotplug.h>
+#include <linux/acpi.h>
#include <asm-generic/pci-bridge.h>
#include <asm/setup.h>
#include "pci.h"
@@ -4501,7 +4502,7 @@ int pci_get_new_domain_nr(void)
void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
{
static int use_dt_domains = -1;
- int domain = of_get_pci_domain_nr(parent->of_node);
+ int domain;
/*
* Check DT domain and use_dt_domains values.
@@ -4523,14 +4524,35 @@ void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
* API and update the use_dt_domains value to keep track of method we
* are using to assign domain numbers (use_dt_domains = 0).
*
+ * IF ACPI, we expect non-DT method (use_dt_domains == -1)
+ * and call _SEG method for corresponding host bridge device.
+ * If _SEG method does not exist, following ACPI spec (6.5.6)
+ * all PCI buses belong to domain 0.
+ *
* All other combinations imply we have a platform that is trying
- * to mix domain numbers obtained from DT and pci_get_new_domain_nr(),
- * which is a recipe for domain mishandling and it is prevented by
- * invalidating the domain value (domain = -1) and printing a
- * corresponding error.
+ * to mix domain numbers obtained from DT, ACPI and
+ * pci_get_new_domain_nr(), which is a recipe for domain mishandling and
+ * it is prevented by invalidating the domain value (domain = -1) and
+ * printing a corresponding error.
*/
+
+ domain = of_get_pci_domain_nr(parent->of_node);
Not sure what you've got here by splitting the original line into two other than an increase
in the change count.
Yes, it does not make sense to split the original line. I will fix that.
Otherwise, it looks sensible.
Reviewed-by: Liviu Dudau <Liviu.Dudau@xxxxxxx>
Thanks Liviu!
Regards,
Tomasz
--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
